Answer: c
Explanation: The function of LPF in PLL is to suppress high frequency components of PD output and presenting DC signal to VCO.

9. Instead of Phase detection, if Frequency detector is used the drawback PLL would face is:
a) Finite difference between input and output frequency
b) Equality cannot be established if PLL compared input and output frequency rather than pulses
c) Error between Vin and Vout cannot be removed
d) All of the mentionedView Answer

Answer: d
Explanation: None.

10. If the input of type 1 PLL is a frequency step of Δw at t = 0, the change in phase at t = infinity is:
a) Δw
b) Δw/Kpd
c) Δw/Kpd.Kvco
d) None of the mentionedView Answer

13. If high pass filter is used instead of Low pass filter in the PLL the response of PLL would be:
a) Output Voltage is not a square wave
b) Output Voltage contains many high frequency waves
c) VCO will be unstable due to variations in control voltage
d) All of the mentionedView Answer